UPDATE 1-Heavy gunfire heard in north Nigerian city hit by insurgency

(Adds details, background)

By Lanre Ola

MAIDUGURI, Nigeria, March 14 (Reuters) - Heavy gunfire raged
for two hours in Nigeria's northeastern city of Maiduguri on
Friday morning, residents said, and explosions were heard at the
Giwa barracks, where the army has detained hundreds of Islamist
insurgent suspects.

Al Qaeda-linked Boko Haram has killed thousands in an almost
five-year-long insurgency aimed at carving out an Islamic state
in the religiously diverse country of about 170 million people.

"The sound of heavy gunfire and what sounds like RPGs
(rocket propelled grenades) began at around 7:15 a.m. and it is
still going," a Reuters witness said. The fighting was happening
at Fori, an area near a military barracks, he said.

Boko Haram is the biggest security threat in Africa's top
oil exporter and the continent's second biggest economy. More
than 2,000 people have been killed in Boko Haram violence in the
last six months, security sources say.

President Goodluck Jonathan intensified the military
campaign almost a year ago to oust insurgents from their
stronghold in the poor and undeveloped northeast but it has
failed to stem the bloodshed.

Violence in recent months has mostly been confined to rural
regions where Boko Haram often gains the upper hand against the
military. An attack on the northeast's biggest city where there
is a heavy army presence would be a setback for Jonathan.

Western governments are concerned about Boko Haram joining
forces with al Qaeda affiliates operating in the Sahel. The
unrest has already pushed thousands of refugees over the borders
into neighbouring Niger and Cameroon.
(Additional reporting by Isaac Abrak in Kaduna; Writing by Joe
Brock; Editing by Louise Ireland)